In general, a particle beam therapy system used for cancer therapy or the like includes: a beam generation apparatus that generates a charged particle beam; an accelerator that is connected to the beam generation apparatus and accelerates the generated charged particle beam; a beam transport system that transports the charged particle beam emitted from the accelerator after being accelerated thereby up to a preset energy; and a particle beam irradiation apparatus that is placed downstream of the beam transport system, for radiating the charged particle beam to an irradiation subject. In order to radiate the charged particle beam to the irradiation subject at an arbitrary angle, the particle beam irradiation apparatus is placed in a rotary gantry for three-dimensional irradiation.
Charged particles formed into a beam (referred to also as the charged particle beam or a particle beam) that is obtained by circularly accelerating the charged particles by the accelerator (circular accelerator) such as a synchrotron, etc. and taking out the charged particles (protons, carbon ions, etc.) accelerated up to a high energy from its circular trajectory, are transported using the beam transport system so as to be applied to a physical experiment in which an intended object is irradiated therewith or a particle beam therapy such as a cancer therapy, etc. In the cancer therapy by the accelerated charged particles, that is, in the particle beam therapy, in order to keep vital organs away or to prevent normal tissues from being affected at the time of the therapy, changing a direction of the irradiation is generally performed. In order to irradiate the patient from an arbitrary direction, the particle beam irradiation apparatus placed in the aforementioned rotary gantry is used.
The accelerator such as a synchrotron, etc. is configured with: a circular acceleration tube in which the charged particle beam circulates; deflection electromagnets and four-pole electromagnets for controlling the circular trajectory of the charged particle beam; an acceleration cavity that accelerates the charged particle beam using an electric field generated by a high-frequency acceleration voltage; an injection device that introduces the charged particle beam into the acceleration tube; an emission device that takes out the accelerated charged particle beam to the outside; and so on. In order for the charged particle beam to circulate without colliding with the acceleration tube, an alignment that is an adjustment of position, angle, etc. is applied to the deflection electromagnets, the four-pole electromagnets and the like. Further, with respect also to the beam transport system, an alignment that is an adjustment of position, angle, etc. is applied thereto in order for the charged particle beam to be transported to the particle beam irradiation apparatus without colliding with the transport tube.
For example, in Patent Document 1, there is described an alignment system of an electromagnet for a high energy accelerator in which the electromagnet for the accelerator placed on a mounting frame is adjusted in its position and attitude using pluralities of adjusting bolts and actuators. The alignment system of Patent Document 1 includes, for each one of electromagnets, four adjusting bolts for adjusting it in a horizontal direction and four adjusting bolts for adjusting it in a vertical direction, and the respective adjusting bolts are controlled by the actuators.
Meanwhile, in Patent Document 2, there is described an accelerator system in which a pre-accelerator that accelerates a charged particle beam and a synchrotron that further accelerates the charged particle beam emitted from the pre-accelerator, are sterically arranged. A beam transport means that connects the pre-accelerator and the synchrotron together is arranged vertically. Deflection electromagnets and four-pole electromagnets in the beam transport means are fixed on respective fixing plates, and the fixing plates are arranged perpendicular to the a side face of a plate-like mounting frame fixed to a shielding wall.